Field of Invention
The present invention relates to an optical system.
Description of Related Art
In general, depth of field for an optical system like a projector or a camera is narrow, and the image of the projector projected onto a plane appears sharp only within a small working distance range. Also, the camera can only detect a clear image under a rather limited working distance range. In this regard, if the projection of an image is conducted obliquely or onto a non-flat plane, portions of the image must be located outside the working distance range of the projector. Under such circumstances, it is difficult to obtain an entire sharp image, and the camera has to detect an unfocused image from the non-flat plane. Therefore, the industry is striving to provide an optical system to solve the aforementioned issues.